Transmission device and gain control method

ABSTRACT

An apparatus that can lower the possibility of failing reception modulation in communication where data is transmitted with and without directivity and prevent deterioration of transmission efficiency caused by retransmission. With this apparatus, a gain control signal multiplex section ( 203 ) time division multiplexes a directional transmission signal and a gain control signal. A transmission level control section ( 204 ) controls the transmission power level of a gain control signal so that the transmission power level of the gain control signal is smaller than the transmission power level of a directional transmission signal and the received power level of the gain control signal is larger than a received power level of a nondirectional transmission signal at the receiving side, and controls the transmission power level of a directional transmission signal so that the received power level of the directional transmission signal is larger than the received power level of a nondirectional transmission signal and the received power level of a gain control signal at the receiving side.

TECHNICAL FIELD

The present invention relates to a transmission apparatus and gaincontrol method for transmitting data with directivity.

BACKGROUND ART

Conventionally, a base station is known that performs adaptive arrayantenna (hereinafter referred to as “AAA”) transmission according to thecombined weight for each diversity branch obtained upon AAA reception.By using this technique, the reception electric field strength increasesat a mobile station in downlink, and interference against mobilestations connected to another base station which has been interferencesource upon reception decreases.

In a system employing AAA transmission, cases might occur wherenondirectional communication and directional communication both exist(for example, see Patent Document 1.) In the case where nondirectionalsignals as well as directional signals are transmitted—particularly inthe case where AAA is used in downlink—pilot signals and control signalsgenerally required for all terminals are transmitted withoutdirectivity, and dedicated data for each terminal is transmitted withdirectivity. Hereinafter, control signals required for all terminalstransmitted without directivity will be referred to as nondirectionaltransmission signals, and dedicated data for each terminal transmittedwith directivity will be referred to as directional transmissionsignals. In view of received signal level at each terminal, thepossibility is larger that received signal level increases in the casewhere directional signals are received than the case wherenondirectional signals are received. Furthermore, in the case of asystem where data for a terminal is transmitted in bursts, whilenondirectional signals are received at low power level, suddenlydirectional signals at large power level are received.

FIG. 1A and FIG. 1B illustrate relationship between the received powerlevel and the received timing of conventional nondirectional receivedsignals #11, #13 and a directional received signal #12. As shown in FIG.1A, processing of increasing the dynamic range starts for the first timeat time t10 when directional received signal #12 is received. By thismeans, a dynamic range including the power level of directional receivedsignal #12 is set at time t11.

Patent Document 1: Japanese Patent Application Laid-Open No. 2003-134025

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

A conventional transmission apparatus and gain control method generallycontrol the input level of a received signal so that a dynamic range ofa reception analog/digital converter is efficiently used by automaticgain control (AGC) . However, there is a problem that when signal levelsuddenly increases, as shown in FIG. 1B, setting of a dynamic rangesupporting large signal levels is delayed for time (t11-t10) , and, as aresult, automatic gain control cannot follow and reception demodulationfails. When reception demodulation fails, retransmission is required.However, there is a problem that, in the case where directionalcommunication is performed in bursts and lasts only a short time,overhead of retransmission increases and transmission efficiencydeteriorates.

It is therefore an object of the present invention to provide atransmission apparatus and gain control method that make it possible tolower the possibility of failing reception demodulation in communicationwhere data is transmitted with and without directivity and preventdeterioration of transmission efficiency caused by retransmission.

Means for Solving the Problem

The transmission apparatus according to the present invention adopts aconfiguration having a gain control signal generating section thatgenerates a gain control signal that is a signal for adjusting a gainfor a received signal of a communicating party, a gain control signalmultiplex section that time division multiplexes a directionaltransmission signal and the gain control signal so that the gain controlsignal is transmitted a predetermined time before a frame in which thedirectional transmission signal is transmitted in bursts, a transmissionlevel control section that sets a transmission power level of the gaincontrol signal so that a transmission power level of the gain controlsignal is smaller than a transmission power level of the directionaltransmission signal and a received power level of the gain controlsignal is larger than a received power level at a communicating party ofa nondirectional transmission signal, and a transmission section thattransmits the directional transmission signal and the gain controlsignal having the transmission power level set at the transmission levelcontrol section with directivity and transmits the nondirectionaltransmission signal without directivity.

The transmission apparatus according to the present invention adopts aconfiguration having a transmission level control section that sets atransmission power level of a directional transmission signaltransmitted in bursts so that a received power level at a communicatingparty becomes gradually larger up to a predetermined level, and atransmission section that transmits the directional transmission signalat the transmission power level set at the transmission level controlsection with directivity and transmits the nondirectional transmissionsignal without directivity.

The transmission apparatus according to the present invention adopts aconfiguration having a control signal multiplex section that timedivision multiplexes a directional transmission signal and power levelinformation so that power level information that is information of areceived power level at the communicating party of the directionaltransmission signal is transmitted to the communicating party before thedirectional transmission signal is transmitted, and a transmissionsection that transmits with directivity the power level information andthe directional transmission signal multiplexed at the control signalmultiplex section.

A reception apparatus according to the present invention adopts aconfiguration having a received level detecting section that obtains areceived power level of a gain control signal that is a signal foradjusting a gain for a received signal included in the received signaland a received power level of the received signal other than the gaincontrol signal, a gain setting section that sets a gain based on areceived power level of the gain control signal measured at the receivedlevel detecting section and a received power level of the receivedsignal other than the gain control signal, and a gain adjusting sectionthat amplifies a gain for the received signal at the gain set at thegain setting section.

The reception apparatus according to the present invention adopts aconfiguration having a gain setting section that sets a gaincorresponding to power level information that is information indicatinga received power level after a predetermined time included in a receivedsignal, and a gain adjusting section that amplifies the received signalby the gain set at the gain setting section.

A gain control method according to the present invention has steps ofgenerating a gain control signal that is a signal for adjusting a gainfor a received signal of a communicating party, time divisionmultiplexing a directional signal and the gain control signal so thatthe gain control signal is transmitted a predetermined time before aframe in which the directional signal is transmitted in bursts, settinga transmission power level of the gain control signal so that thetransmission power level of the gain control signal is smaller than atransmission power level of the directional signal and a received powerlevel of the gain control signal is larger than a received power levelat a communicating party of a nondirectional signal, transmitting thedirectional signal and the gain control signal at the set transmissionpower level with directivity and transmitting the nondirectional signalwithout directivity, and controlling a gain at a dynamic range includingthe received power level of the received nondirectional signal, gaincontrol signal and directional signal.

A gain control method according to the present invention has steps ofsetting a transmission power level of a directional signal transmittedin bursts so that a received power level at a communicating partybecomes gradually larger up to a predetermined level, transmitting thedirectional signal at the set transmission power level with directivityand transmitting the nondirectional signal without directivity, andcontrolling a gain at a dynamic range including the received power levelof the received nondirectional signal and directional signal.

ADVANTAGEOUS EFFECT OF THE INVENTION

According to the present invention, in communication where data istransmitted with and without directivity, it is possible to lower thepossibility of failing reception demodulation and prevent deteriorationof transmission efficiency caused by retransmission.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A illustrates relationships between the conventional receivedpower level and the received timing;

FIG. 1B illustrates the conventional change of the range of a dynamicrange of AGC as time passes;

FIG. 2 is a block diagram showing a configuration of atransmission/reception apparatus according to Embodiment 1 of thepresent invention;

FIG. 3 is a block diagram showing a configuration of a directionalsignal generating section according to Embodiment 1 of the presentinvention;

FIG. 4 is a block diagram showing a configuration of atransmission/reception apparatus according to Embodiment 1 of thepresent invention;

FIG. 5A illustrates relationships between the received power level andthe received timing according to Embodiment 1 of the present invention;

FIG. 5B illustrates the change of the range of a dynamic range of AGC astime passes according to Embodiment 1 of the present invention;

FIG. 6 is a block diagram showing a configuration of atransmission/reception apparatus according to Embodiment 2 of thepresent invention;

FIG. 7 is a block diagram showing a configuration of a directionalsignal generating section according to Embodiment 2 of the presentinvention;

FIG. 8 is a block diagram showing a configuration of atransmission/reception apparatus according to Embodiment 2 of thepresent invention;

FIG. 9 illustrates relationships between the received power level andthe received timing according to Embodiment 2 of the present invention;

FIG. 10 is a block diagram showing a configuration of a directionalsignal generating section according to Embodiment 3 of the presentinvention;

FIG. 11 illustrates relationships between the received power level andthe received timing according to Embodiment 3 of the present invention;

FIG. 12 is a block diagram showing a configuration of a directionalsignal generating section according to Embodiment 4 of the presentinvention;

FIG. 13 illustrates relationships between the received power level andthe received timing according to Embodiment 4 of the present invention;

FIG. 14 illustrates an MCS table according to Embodiment 4 of thepresent invention;

FIG. 15 is a block diagram showing a configuration of a directionalsignal generating section according to Embodiment 5 of the presentinvention;

FIG. 16 illustrates relationships between the received power level andthe received timing according to Embodiment 5 of the present invention;

FIG. 17 is a block diagram showing a configuration of atransmission/reception apparatus according to Embodiment 6 of thepresent invention;

FIG. 18 is a block diagram showing a configuration of atransmission/reception apparatus according to Embodiment 6 of thepresent invention; and

FIG. 19 illustrates relationships between the received power level andthe received timing according to Embodiment 6 of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described in detail belowwith reference to the accompanying drawings.

Embodiment 1

FIG. 2 is a block diagram showing a configuration of atransmission/reception apparatus according to Embodiment 1 of thepresent invention.

Switching sections 102-1 to 102-n switch between outputting receivedsignals received at antennas 101-1 to 101-n to RF sections 103-1 to103-n and transmitting transmission signals inputted from RF sections114-1 to 114-n from antennas 101-1 to 101-n.

RF sections 103-1 to 103-n down-convert received signals inputted fromswitching sections 102-1 to 102-n from radio frequency to basebandfrequency, and output the results to detecting sections 104-1 to 104-n.

Detecting section 104-1 performs quadrature detection on a receivedsignal inputted from RF section 103-1 and outputs the quadraturedetection result to weight calculation section 105 and multiplier 106-1.That is, detecting section 104-1 performs quadrature detection on areceived signal inputted from RF section 103-1 and thereby outputs acomplex baseband signal in which the I component and Q component arerespectively the real part and imaginary part, to weight calculationsection 105, multiplier 106-1 and directional signal generating section111.

Detecting sections 104-2 to 104-n perform quadrature detection onreceived signals inputted from RF sections 103-2 to 103-n and output thequadrature detection results to weight calculation section 105 andmultipliers 106-2 to 106-n. That is, detecting sections 104-2 to 104-nperform quadrature detection on received signals inputted from RFsections 103-2 to 103-n, and output complex baseband signals in whichthe I component and Q component are respectively the real part andimaginary part, to weight calculation section 105 and multipliers 106-2to 106-n.

Weight calculation section 105 calculates combined weight where desiredsignals reinforce each other and interference signals cancel each other,according to the baseband signals inputted from detecting sections 104-1to 104-n, and outputs the calculated combined weight to multipliers106-1 to 106-n, and outputs information of the calculated combinedweight to phase difference calculation section 108.

Multipliers 106-1 to 106-n assign weight by multiplying the basebandsignals inputted from detecting sections 104-1 to 104-n by the combinedweight inputted from weight calculation section 105, and output theweighted baseband signals to combining section 107.

Combining section 107 performs additive combining with the weightedbaseband signals inputted from multipliers 106-1 to 106-n, and outputsthe results to directional signal generating section 111, and obtainsreceived data.

Phase difference calculation section 108 detects the phase difference ofeach branch from information of the combined weight inputted from weightcalculation section 105, and outputs the result to code inversionsection 109.

Code inversion section 109 inverts the positivity and negativity of thesignals in phase difference information of each branch inputted fromphase difference calculation section 108 and outputs the result tomultipliers 112-1 to 112-n.

Modulation section 110 modulates the inputted nondirectionaltransmission data, generates a nondirectional transmission signal, andoutputs the generated nondirectional transmission signal to adder 113.

Directional signal generating section 111 modulates directionaltransmission data, generates a directional transmission signal, timedivision multiplexes the directional transmission signal and the gaincontrol signal based on timing control information, and generates adirectional transmission signal to transmit in bursts. The directionaltransmission signal is, for example, dedicated data of dedicated channeland is unique data for each communicating party. The gain control signalis a signal that has a predetermined power level and is used upon gaincontrol at a receiving side and is not used to transmit data.Furthermore, directional signal generating section 111 sets thetransmission power level of the gain control signal and the transmissionpower level of the directional transmission signal. After setting of thetransmission power level and the processing of time divisionmultiplexing are completed, directional signal generating section 111outputs a directional signal composed of a gain control signal and adirectional transmission signal to multipliers 112-1 to 112-n. Inaddition, directional signal generating section 111 will be described indetail below.

Multipliers 112-1 to 112-n multiply the phase difference from phasedifference information which is the information after phase inversioninputted from code inversion section 109 by the directional transmissionsignal inputted from directional signal generating section 111.Multiplier 112-1 multiplies the phase difference by the directionaltransmission signal and outputs the result to adder 113, and multipliers112-2 to 112-n multiply phase differences by the directionaltransmission signals and output the results to RF sections 114-2 to114-n.

Adder 113 adds the directional transmission signal inputted frommultiplier 112-1 and the nondirectional transmission signal inputtedfrom modulation section 110, and outputs the result to RF section 114-1.

RF section 114-1 up-converts the directional transmission signal andnondirectional signal inputted from adder 113 from base band frequencyto radio frequency, and amplifies them to predetermined transmissionlevel and outputs them to switching section 102-1.

RF sections 114-2 to 114-n up-convert the signals in which phasedifference inputted from multipliers 112-2 to 112-n is multiplexed bythe directional transmission signals from baseband frequency to radiofrequency, amplify them to a predetermined transmission level, andoutput the results to switching sections 102-2 to 102-n.

Directional signal generating section 111 will be described in detailbelow using FIG. 3. FIG. 3 is a block diagram showing a configuration ofdirectional signal generating section 111.

When timing control information is inputted at a timing two framesbefore the frame in which a directional transmission signal istransmitted, gain control signal generating section 201 generates andoutputs to gain control signal multiplex section 203 a gain controlsignal When the gain control signal is outputted to gain control signalmultiplex section 203, gain control signal generating section 201outputs timing information indicating a timing when the gain controlsignal has been outputted, to transmission level control section 204.

Modulation section 202 modulates the directional transmission data andoutputs the result to gain control signal multiplex section 203.

Gain control signal multiplex section 203 time division multiplexes thedirectional transmission signal inputted from modulation section 202 andthe gain control signal inputted from gain control signal generatingsection 201, and outputs time division multiplexed directionaltransmission signal and gain control signal to transmission levelcontrol section 204.

When a timing control signal is not inputted from gain control signalgenerating section 201, transmission level control section 204 controlsthe transmission power level so that the received power level of thedirectional transmission signal at the receiving side that is acommunicating party is larger than the received power level of thenondirectional transmission signal at the receiving side. Furthermore,transmission level control section 204 controls the transmission powerlevel so that at the timing when a timing control signal is inputtedfrom gain control signal generating section 201, the transmission powerlevel of the gain control signal time division multiplexed by gaincontrol signal multiplex section 203 is smaller than the transmissionpower level of the directional transmission signal, and the receivedpower level is larger than the received power level of thenondirectional transmission signal at the receiving side. Transmissionlevel control section 204 also controls the transmission power level ofthe directional transmission signal so that at the timing when thedirectional transmission signal time division multiplexed by gaincontrol signal multiplex section 203 is inputted, the received powerlevel of the directional transmission signal is larger than the receivedpower level of the nondirectional transmission signal and the gaincontrol signal at the receiving side. After the transmission power levelis set, transmission level control section 204 outputs the directionaltransmission signal and the gain control signal to multipliers 112-1 to112-n. As a method for controlling transmission power level of the gaincontrol signal so that the received power level of the gain controlsignal is larger than the received power level of the nondirectionaltransmission signal at the receiving side, transmission control section204 obtains a received power level ratio between the received signal atone antenna 101-1 inputted from detecting section 104-1 and the receivedsignal received with directivity inputted from combining section 107,and sets the transmission power level of the gain control signal so thata value dividing the transmission power level of the gain control signalby the obtained received power level ratio of the received signal at oneantenna 101-1 and the received power level of the received signalreceived with directivity is larger than the transmission power level ofthe nondirectional transmission signal. The power level required fortransmitting the directional transmission signal and nondirectionaltransmission signal varies between systems.

A configuration of transmission/reception apparatus 300 that is acommunicating party of transmission/reception apparatus 100 will bedescribed below using FIG. 4. FIG. 4 is a block diagram showing aconfiguration of transmission/reception apparatus 300.

Switching section 302 switches between outputting received signalsreceived at antenna 301 to RF section 303 and transmitting transmissionsignals inputted from RF section 310 from antenna 301.

RF section 303 down-converts a received signal inputted from switchingsection 302 from radio frequency to baseband frequency and outputs theresult to variable gain amplifier 304.

Variable gain amplifier 304 is a gain adjusting means and an amplifierhaving a variable gain, amplifies the received signal by control of gainswitching section 308. Demodulation section 305 demodulates the receivedsignal and obtains received data.

Received level detecting section 306 measures the received level of thereceived signal inputted from variable gain amplifier 304, and outputsmeasurement value information that is information of measurement valueof the received level to AGC control section 307. When the gain controlsignal is received, received level detecting section 306 measures largerreceived level than the received level in the case where thenondirectional transmission signal is received and smaller receivedlevel than the received level in the case where the directionaltransmission signal is received, as the received level of the gaincontrol signal.

AGC control section 307 is a gain setting means and determines a gainfor variable gain amplifier 304 so that the received level measured byreceived level detecting section 306 is a predetermined received level,and outputs gain information, which is information of the determinedgain, to gain switching section 308. Specifically, when a gain controlsignal is not received, AGC control section 307 averages the measurementvalues of the received level over a predetermined time and obtains anaverage value from measurement value information of the received levelinputted from received level detecting section 306 and determines a gaincorresponding to the average value of the obtained received level. Onthe other hand, when a gain control signal is received, AGC controlsection 307 cancels the processing of averaging measurement values ofthe received level and determines a gain corresponding to themeasurement value of the received level from measurement valueinformation of the received level of the gain control signal inputtedfrom received level detecting section 306. Until a directionaltransmission signal transmitted from transmission/reception apparatus100 is received, AGC control section 307 updates and holds the gain thatis set based on the received level of the gain control signal every timea gain control signal is received. AGC control section 307 can learn thetiming when the gain control signal is inputted from timing controlinformation. The timing when the gain control signal is inputted ispredetermined by system or is reported by control information.

Gain switching section 308 controls variable gain amplifier 304 to havethe gain specified by gain information inputted from AGC control section307. Therefore, desired gain information is inputted from AGC controlsection 307 at the timing when the gain control signal is received, andthereby gain switching section 308 sets the desired gain before AGC isperformed on the directional transmission signal.

Modulation section 309 modulates transmission data and outputs theresult to RF section 310.

RF section 310 up-converts the transmission data inputted frommodulation section 309 from baseband frequency to radio frequency andoutputs the result to switching section 302.

FIG. 5A illustrates relationships between the received timing and thereceived power level of nondirectional received signals #401 and #405,directional received signal #404, and gain control signals #402 and #403received at transmission/reception apparatus 300 at the receiving side.FIG. 5B illustrates the change of the range of a dynamic range of AGC astime passes. In FIG. 5B, solid line #406 is the range of a dynamic rangein the case where gain control signals #402 and #403 are received anddotted line #407 is the range of a dynamic range in the case where gaincontrol signals #402 and #403 are not received. As shown in FIG. 5A andFIG. 5B, the received power level of directional received signal #404 isconsiderably larger than the received power level of nondirectionalreceived signals #401 and #405. The time axis in FIG. 5A is correspondedwith the time axis in FIG. 5B.

As shown in FIG. 5A, at time t1 when the frame two frames before theframe including directional received signal #404 is received,transmission/reception apparatus 300 receives gain control signal #402at a power level larger than the power level of nondirectional receivedsignal #401 and smaller than the power level of directional receivedsignal #404. By this means, a gain is controlled at the receiving sideaccording to the received level of gain control signal #402, andtherefore, as shown in FIG. 5B, the dynamic range can be increased fromtime t1. Further, in the next frame of the frame including gain controlsignal #402, transmission/reception apparatus 300 receives gain controlsignal #403 at a power level larger than the power level ofnondirectional received signal #401 and gain control signal #402 andsmaller than the power level of directional received signal #404. Bythis means, transmission/reception apparatus 300 controls a gainaccording to gain control signal #402, and thereby, at time t2 whendirectional received signal #404 is received, sets a dynamic rangeincluding the power level of directional received signal #404.

On the other hand, when a conventional dynamic range indicated by thedotted line in FIG. 5B is set, gain control signals #402 and #403 arenot received, and at time t2 when directional received signal #404 isreceived, the processing of increasing a dynamic range starts for thefirst time, and thereby a dynamic range including the power level ofdirectional received signal #404 is set at time t3, and, compared to thecase where gain control signals #402 and #403 are transmitted, time isdelayed for (t3-t2) when a dynamic range including the power level ofdirectional received signal #404 is set.

In this way, according to Embodiment 1, a gain control signal where thetransmission power level is set so that the transmission power level ofthe gain control signal is smaller than the transmission power level ofa directional transmission signal and the received power level of thegain control signal is larger than the received power level of anondirectional transmission signal at the receiving side, is transmittedpredetermined frames before the frame in which the transmission of adirectional transmission signal starts, thereby making it possible toset at the receiving side a large dynamic range based on received powerlevel of the gain control signal before the directional transmissionsignal is received. By this means, it is possible to lower thepossibility of failing reception demodulation and prevent deteriorationof transmission efficiency caused by retransmission. According toEmbodiment 1, a gain control signal is transmitted with directivity, sothat it is possible to prevent increasing interference against otherreception apparatus.

A case has been explained in Embodiment 1 where a gain control signal istransmitted twice at predetermined interval, but this is by no meanslimiting and is also applicable to cases where a gain control signal istransmitted three times or more at predetermined intervals orcontinuously transmitted in a predetermined period. Furthermore, a casehas been explained in Embodiment 1 where a gain control signal istransmitted for each frame, but this is by no means limiting and is alsoapplicable to cases where a gain control signal is transmitted at anarbitrary timing such as for each slot. Still further, a case has beenexplained in Embodiment 1 where a gain control signal is transmitted inthe frame two frames before the frame in which the transmission of thedirectional transmission signal starts, but this is by no means limitingand is also applicable to cases where a gain control signal istransmitted in other frames than the frame two frames before the framein which the transmission of the directional transmission signal startsor in the same frame as the frame in which the transmission of thedirectional transmission signal starts.

Embodiment 2

FIG. 6 is a block diagram showing a configuration oftransmission/reception apparatus 500 according to Embodiment 2 of thepresent invention.

As shown in FIG. 6, a transmission/reception apparatus 500 according toEmbodiment 2 of the present invention adds spreading section 501 totransmission/reception apparatus 100 according to Embodiment 1 shown inFIG. 2. In addition, parts in FIG. 6 that have identical configurationswith ones in FIG. 2 will be assigned the same codes as in FIG. 2 withoutfurther explanations. Furthermore, a reception apparatus that is acommunicating party of transmission/reception apparatus 500 has the sameconfiguration as FIG. 4, and therefore the explanation thereof isomitted.

Spreading section 501 performs spreading processing on a nondirectionaltransmission signal inputted from modulation section 110 usingpredetermined spreading codes and outputs the result to adder 113.

Adder 113 is a code multiplex means and adds a directional transmissionsignal inputted from adder 112-1 and a nondirectional transmissionsignal inputted from spreading section 501, and thereby code multiplexesthe gain control signal and the nondirectional transmission signal andoutputs the result to RF section 114-1.

Next, a configuration of directional signal generating section 111 willbe described using FIG. 7. FIG. 7 is a block diagram of a configurationof directional signal generating section 111.

As shown in FIG. 7, directional signal generating section 111 accordingto Embodiment 2 of the present invention removes gain control signalmultiplex section 203 from directional signal generating section 111according to Embodiment 1 as shown in FIG. 3, and adds spreading section601. In addition, parts in FIG. 7 that have identical configurationswith ones in FIG. 3 will be assigned the same codes as in FIG. 3 withoutfurther explanations.

Spreading section 601 performs spreading processing and time divisionmultiplexing on a directional transmission signal inputted frommodulation section 202 and a gain control signal inputted from gaincontrol signal generating section 201 using predetermined spreadingcodes, generates a directional transmission signal, and outputs thegenerated directional transmission signal to transmission level controlsection 204.

Transmission level control section 204 controls the transmission powerlevel so that in the case where timing control signal is not inputtedfrom gain control signal generating section 201 the received power levelof the directional transmission signal at the receiving side is largerthan the received power level of the nondirectional transmission signal.Furthermore, transmission level control section 204 controls thetransmission power level so that in the case where a timing controlsignal is inputted from gain control signal generating section 201 atthe timing when a time multiplexed gain control signal is inputted fromspreading section 601, the transmission power level of the gain controlsignal is smaller than the transmission power level of the directionaltransmission signal, and a transmission power level becomes higher asthe frame in which the directional transmission signal is transmitted isapproached, and at the timing when the time division multiplexeddirectional transmission signal is inputted from spreading section 601,the transmission power level of the directional transmission signal issufficiently larger than the received power level of the nondirectionaltransmission signal and the gain control signal at the receiving side.Then, transmission level control section 204 outputs a directionaltransmission signal and gain control signal to adder 112-1 to 112-nafter a transmission power level is set.

Next, a configuration of transmission/reception apparatus 700 that is acommunicating party of transmission/reception apparatus 500 will bedescribed using FIG. 8. FIG. 8 is a block diagram showing aconfiguration of transmission/reception apparatus 700.

As shown in FIG. 8, transmission/reception apparatus 700 according toEmbodiment 2 adds despreading section 701 to transmission/receptionapparatus 300 according to Embodiment 1 shown in FIG. 4. In addition,parts in FIG. 8 that have identical configurations with ones in FIG. 4will be assigned the same codes as in FIG. 4 without furtherexplanations.

Received level detecting section 306 measures the received level of areceived signal inputted from variable gain amplifier 304 and outputsthe measurement result to AGC control section 307. Therefore, receivedlevel detecting section 306 measures a larger received level in the casewhere a received signal in which a gain control signal and anondirectional transmission signal are code multiplexed is received thanthe received level in the case where only nondirectional signal isreceived, and a smaller received level than the received level in thecase where a received signal in which a directional transmission signaland a nondirectional transmission signal are code multiplexed isreceived, as the received level of the received signal in which a gaincontrol signal and a nondirectional transmission signal are codemultiplexed.

AGC control section 307 determines a gain for variable gain amplifier304 so that the received level measured at received level detectingsection 306 is a desired received level, and outputs the gaininformation that is information of the determined gain to gain switchingsection 308. That is, AGC control section 307 averages the measurementresults of the received level inputted from received level detectingsection 306 over a predetermined time and determines a gain according tothe averaged received level. In addition, AGC control section 307performs the same processing in the case where a received signal inwhich a gain control signal and a nondirectional transmission signal arecode multiplexed is inputted as in the case where a received signal inwhich a directional transmission signal and a nondirectionaltransmission signal are code multiplexed is inputted and the case whereonly nondirectional transmission signal is inputted.

Despreading section 701 despreads the received signal inputted fromvariable gain amplifier 304 and outputs the results to demodulationsection 305.

FIG. 9 illustrates relationships between the received timing and thereceived power level of nondirectional received signal #801, directionalreceived signal #804 and gain control signal #802 and #803, received ata reception apparatus. In addition, a view showing the change of therange of a dynamic range of AGC as time passes is the same as FIG. 5B,therefore the explanation thereof is omitted.

As shown in FIG. 9, a reception apparatus receives a received signal inwhich nondirectional received signal #801 and gain control signal #802are code multiplexed at time t1 when a frame two frames before the frameincluding directional received signal #804 is received. The receivedsignal in which nondirectional received signal #801 and gain controlsignal #802 are code multiplexed has a larger power level correspondingto the gain control signal #802 multiplex than the power level ofnondirectional received signal #801. Furthermore, a received signal inwhich nondirectional received signal #801 and gain control signal #802are code multiplexed has a smaller power level than the power level of areceived signal in which nondirectional received signal #801 anddirectional received signal #804 are code multiplexed. Therefore,transmission/reception apparatus 700 at the receiving side, controls again according to the received power level of a received signal in whichgain control signal #802 and nondirectional transmission signal #801 arecode multiplexed, thereby making it possible to increase a dynamic rangefrom time t1.

Furthermore, transmission/reception apparatus 700 receives a receivedsignal in which nondirectional received signal #801 and gain controlsignal #803 are code multiplexed in the next frame of the frameincluding gain control signal #802. The received signal in whichnondirectional received signal #801 and gain control signal #803 arecode multiplexed has a larger power level corresponding to the gaincontrol signal #803 multiplex than the power level of nondirectionalreceived signal #801. The power level of gain control signal #803 islarger than the power level of gain control signal #802, and thereforeis larger than the power level of a received signal in whichnondirectional received signal #801 and gain control signal #802 arecode multiplexed. In addition, a received signal in which nondirectionalreceived signal #801 and gain control signal #803 are code multiplexedhas a smaller power level than the power level of a received signal inwhich nondirectional received signal #801 and directional receivedsignal #804 are code multiplexed. By this means, transmission/receptionapparatus 700 performs gain control according to the received powerlevel of a received signal in which gain control signal #803 andnondirectional transmission signal #801 are code multiplexed, therebymaking it possible to set a dynamic range including the power level of areceived signal in which nondirectional received signal #801 anddirectional received signal #804 are code multiplexed at time t2.

In this way, according to Embodiment 2, in addition to the aboveadvantages of Embodiment 1, a gain control signal and a nondirectionaltransmission signal are code multiplexed, and thereby the overall powerlevel of received signals becomes gradually larger after a gain controlsignal is received until a directional transmission signal is received,therefore at the transmitting side and receiving side without beingaware of the timing when a gain control signal is transmitted andreceived, it is possible to perform normal AGC processing of averagingthe received power level over a predetermined time and simplify the AGCprocessing.

A case has been explained in Embodiment 2 where a gain control signal istransmitted continuously from time t1 to time t2, but this is by nomeans limiting and is also applicable to cases where a gain controlsignal is transmitted once or a plurality of times at predeterminedintervals. In addition, a case has been explained in Embodiment 2 wherethe power level of a gain control signal is made different for eachframe, but this is by no means limiting and is also applicable to caseswhere the power level of a gain control signal is made different at anarbitrary timing such as for each slot. Furthermore, a case has beenexplained in Embodiment 2 where the transmission of gain control signalsstarts in the frame two frames before the frame in which thetransmission of directional transmission signals starts, but this is byno means limiting and is also applicable to cases where the transmissionof gain control signals starts in other frames than the frame two framesbefore the frame in which the transmission of directional transmissionsignals starts.

Embodiment 3

FIG. 10 is a block diagram showing a configuration of directional signalgenerating section 111 according to Embodiment 3 of the presentinvention.

As shown in FIG. 10, directional signal generating section 111 accordingto Embodiment 3 of the present invention has modulation section 901 inplace of modulation section 202 and transmission level control section903 in place of transmission level controls section 204, removes gaincontrol signal generating section 201 and gain control signal multiplexsection 203, and adds spreading section 902, in directional signalgenerating section 111 according to Embodiment 1 shown in FIG. 3. Inaddition, parts in FIG. 10 that have identical configurations with onesin FIG. 3 will be assigned the same codes as in FIG. 3 without furtherexplanations. Configurations of a transmission/reception apparatus and areception apparatus that is a communicating party of atransmission/reception apparatus has the same configurations as FIG. 2and FIG. 4, and therefore the explanation thereof is omitted.

Modulation section 901 modulates directional transmission data,generates a directional transmission signal, and outputs the generateddirectional transmission signal to spreading section 902.

Spreading section 902 performs spreading processing on the directionaltransmission signal inputted from modulation section 901 using apredetermined spreading code and outputs the result to transmissionlevel control section 903.

In the case where timing control information is inputted, transmissionlevel control section 903 sets the transmission power level of thedirectional transmission signal inputted from spreading section 902 soas to become gradually larger up to a predetermined level for eachframe. Transmission level control section 903 outputs a directionaltransmission signal to multipliers 112-1 to 112-n after the transmissionpower level is set.

FIG. 11 illustrates relationships between the received timing andreceived power level of nondirectional received signal #1001 anddirectional received signals #1002, #1003 and #1004 received at areception apparatus. A view showing the change of the range of thedynamic range of AGC as time passes is the same as FIG. 5B, andtherefore the explanation thereof is omitted.

As shown in FIG. 11, a transmission/reception apparatus receives areceived signal in which nondirectional received signal #1001 anddirectional received signal #1002 are code multiplexed at time t1 whenthe frame two frames before the frame including directional receivedsignal #1004 is received. A received signal in which nondirectionalreceived signal #1001 and directional received signal #1002 are codemultiplexed has a larger power level corresponding to the directionalreceived signal #1002 multiplex than the power level of nondirectionalreceived signal #1001. A received signal in which nondirectionalreceived signal #1001 and directional received signal #1002 are codemultiplexed has a smaller power level than the power level of a receivedsignal in which nondirecitonal received signal #1001 and directionalreceived signal #1004 are code multiplexed. Therefore, atransmission/reception apparatus at the receiving side, controls a gainaccording to the received power level of a received signal in whichnondirectional transmission signal #1001 and directional transmissionsignal #1002 are code multiplexed, thereby making it possible toincrease a dynamic range from time t1.

Furthermore, the transmission/reception apparatus receives a receivedsignal in which nondirectional received signal #1001 and directionalreceived signal #1003 are code multiplexed in the next frame of theframe including a received signal in which nondirectional receivedsignal #1001 and directional received signal #1002 are code multiplexed.A received signal in which nondirectional received signal #901 anddirectional received signal #1003 are code multiplexed has a largerpower level corresponding to the directional received signal #1003multiplex than the power level of directional received signal #1003. Thepower level of directional received signal #1003 has a larger powerlevel than the power level of directional received signal #1002, andtherefore has a larger power level than the power level of a receivedsignal in which nondirectional received signal #1001 and directionalreceived signal #1002 are code multiplexed. A received signal in whichnondirectional received signal #1001 and directional received signal#1003 are code multiplexed has a smaller power level than the powerlevel of the received signal in which nondirectional received signal#1001 and directional received signal #1004 are code multiplexed.Therefore, the transmission/reception apparatus at the receiving side,controls a gain according to the received power level of a receivedsignal in which nondirectional received signal #1001 and directionalreceived signal #1003 are code multiplexed, thereby making it possibleto set a dynamic range including the power level of a received signal inwhich nondirectional received signal #1001 and directional receivedsignal #1004 are code multiplexed at time t2.

In this way, according to Embodiment 3, in addition to the aboveadvantages of Embodiment 1, the power level of a directionaltransmission signal is set so that the power level of a directionaltransmission signal becomes gradually larger up to a predeterminedvalue, therefore dynamic range can be adjusted using a directionaltransmission signal transmitting data, thereby making it possible toeffectively use radio resources.

In addition, a case has been explained in Embodiment 3 where the powerlevel is made different for each frame, but this is by no means limitingand is also applicable to cases where the power level is made differentat an arbitrary timing such as for each slot. Furthermore, a case hasbeen explained in Embodiment 3 where directional transmission signals#1002 and #1003 controlling a gain and a nondirectional transmissionsignal are code multiplexed, but this is by no means limiting and isalso applicable to cases where, when directional transmission signals#1002 and #1003 are transmitted, a nondirectional transmission signal isnot transmitted. Still further, a case has been explained in Embodiment3 where directional transmission signal #1004 is controlled so that thepower level of a received signal becomes gradually larger in the frametwo frames before the frame in which directional transmission signal#1004 of a predetermined power level is received for the first time, butthe present invention is not limited to this and is also applicable tocases where the power level of a directional transmission signal iscontrolled so that the power level of a received signal of a directionaltransmission signal at the receiving side becomes gradually larger inother frames than the frame two frames before the frame in whichdirectional transmission signal #1004 of a predetermined power level isreceived for the first time.

Embodiment 4

FIG. 12 is a block diagram showing a configuration of directional signalgenerating section 111 according to Embodiment 4 of the presentinvention.

As shown in FIG. 12, directional signal generating section 111 accordingto Embodiment 4 removes gain control signal generating section 201 andgain control signal multiplex section 203, has modulation section 1103in place of modulation section 202 and transmission level controlsection 1105 in place of transmission level control section 204, andadds MCS selection section 1101, error correcting coding section 1102and spreading section 1104, in directional signal generating section 111according to Embodiment 1 shown in FIG. 3. In addition, parts in FIG. 12that have identical configurations with ones in FIG. 3 will be assignedthe same codes as in FIG. 3 without further explanations. Configurationsof a transmission/reception apparatus and a reception apparatus that isa communicating party of a transmission/reception apparatus has the sameconfigurations as FIG. 2 and FIG. 4, and therefore the explanationthereof is omitted.

MCS selection section 1101 is a transmission rate selecting means andhas an MCS table holding MCS selection information, and, in the casewhere timing control information is inputted, selects an MCS for adirectional transmission signal based on received quality informationsuch as CQI (Channel Quality Indicator) that is information of receivedquality for each communicating party. That is, MCS selection section1101 selects MCS's so that the transmission rate becomes sequentiallyhigher from a directional transmission signal of a small transmissionpower level to a directional transmission signal of the predeterminedlargest transmission power level. MCS selection section 1101 outputs thecoding rate information that is information indicating coding rate toerror correcting coding section 1102 by the selected MCS, outputsmodulation scheme information that is information indicating themodulation scheme to modulation section 1103, and outputs spreadingfactor information indicating the spreading factor to spreading section1104. MCS selection section 1101 outputs timing control informationindicating a timing when MCS selection starts to transmission levelcontrol section 1105.

Error correcting coding section 1102 codes the directional transmissionsignal at the coding rate of the coding rate information inputted fromMCS selection section 1101 and outputs the result to modulation section1103.

Modulation section 1103 modulates the directional transmission signalinputted from error correcting coding section 1102 in modulation schemeof modulation scheme information inputted from MCS selection section1101, and generates a directional transmission signal and outputs thegenerated directional transmission signal to spreading section 1104.

Spreading section 1104 performs spreading processing on the directionaltransmission signal inputted from modulation section 1103 at thespreading factor of spreading factor information inputted from MCSselection section 1101, and outputs the result to transmission levelcontrol section 1105.

Transmission level control section 1105 sets the transmission powerlevel of a directional transmission signal inputted from spreadingsection 1104 at a predetermined timing from timing control informationinputted from MCS selection section 1101 so that the transmission powerlevel becomes gradually larger up to a predetermined level for eachframe. Transmission level control section 1105 outputs the directionaltransmission signal to multipliers 112-1 to 112-n after the transmissionpower level is set.

FIG. 13 illustrates relationships between the received timing and thereceived power level of nondirectional received signal #1201 anddirectional received signal #1202, #1203, and #1204 received at areception apparatus. In addition, a view showing the change of the rangeof the dynamic range of AGC as time passes is the same as FIG. 5B,therefore the explanation thereof is omitted.

As shown in FIG. 13, a transmission/reception apparatus receives areceived signal in which nondirectional received signal #1201 anddirectional received signal #1202 are code multiplexed at time t1 whenthe frame two frames before the frame including directional receivedsignal #1204 is received. A received signal in which nondirectionalreceived signal #1201 and directional received signal #1202 are codemultiplexed has a larger power level corresponding to the directionalreceived signal #1202 multiplex than the power level of nondirectionalreceived signal #1201. Furthermore, the received signal in whichnondirectional received signal #1201 and directional received signal#1202 are code multiplexed has a smaller power level than the powerlevel of a received signal in which nondirectional received signal #1201and directional received signal #1204 are code multiplexed. Therefore, atransmission/reception apparatus at the receiving side controls a gainaccording to the received power level of the received signal in whichnondirectional received signal #1201 and directional received signal#1202 are code multiplexed, thereby making it possible to increase thedynamic range from time t1.

Furthermore, the transmission/reception apparatus receives a receivedsignal in which nondirectional received signal #1201 and directionalreceived signal #1203 are code multiplexed in the next frame of theframe including the received signal in which nondirectional receivedsignal #1201 and directional received signal #1202 are code multiplexed.The received signal in which nondirectional received signal #1201 anddirectional received signal #1203 are code multiplexed has a largerpower level corresponding to the directional received signal #1203multiplex than the power level of nondirectional received signal #1201.The power level of directional received signal #1203 is larger than thepower level of directional received signal #1202, therefore is largerthan the power level of the received signal in which nondirectionalreceived signal #1201 and directional received signal #1202 are codemultiplexed. Furthermore, the received signal in which nondirectionalreceived signal #1201 and directional received signal #1203 are codemultiplexed has a smaller power level than the power level of a receivedsignal in which nondirectional received signal #1201 and directionalreceived signal #1204 are code multiplexed. Therefore, thetransmission/reception apparatus at the receiving side, controls a gainaccording to the received power level of the received signal in whichnondirectional received signal #1201 and directional received signal#1203 are code multiplexed, thereby making it possible to set a dynamicrange including the power level of the received signal in whichnondirectional received signal #1201 and directional received signal#1204 are code multiplexed at time t2.

MCS selection section 1101 has an MCS table shown in FIG. 14. MCSaccording to the transmission power level is set to directional receivedsignals #1202, #1203 and #1204 at MCS selection section 1101. That is,MCS=2 is set for directional received signal #1202, MCS=3 is set fordirectional received signal #1203, and MCS=4 is set for directionalreceived signal #1204. Here, the transmission rate becomes larger inorder of MCS=1, MCS=2, MCS=3, and MCS=4. Therefore, unless the codingrate changes, the transmission rate becomes higher in response to anincrease in the number of M-ary modulation level, and unless modulationscheme changes, the transmission rate becomes larger in response to anincrease in the coding rate. In this way, modulation scheme and codingrate vary according to the selected MCS so that directional transmissionsignal subjected to spreading processing, modulated, and coding indifferent modulation scheme and at different coding rate according tothe selected MCS.

In this way, according to Embodiment 4, in addition to the aboveadvantages of Embodiment 1 and Embodiment 3, the transmission powerlevel of a directional transmission signal is set to rise gradually upto a predetermined level, and MCS is selected according to thetransmission power level so that it is possible to prevent deteriorationof error rate characteristic and reliably perform reception demodulationat the receiving side.

In addition, a case has been explained in Embodiment 4 where the powerlevel is made different for each frame, but this is by no means limitingand is also applicable to cases where the power level is made differentat an arbitrary timing such as for each slot. Furthermore, a case hasbeen explained in Embodiment 4 where directional transmission signal#1202 and #1203 subject to gain control and a nondirectionaltransmission signal are code multiplexed, but this is by no meanslimiting and is also applicable to cases where a nondirectionaltransmission signal is not transmitted when directional transmissionsignal #1202 and #1203 are transmitted. Still further, a case has beenexplained where the MCS table shown in FIG. 14 is used, but this is byno means limiting and is also applicable to cases where an MCS tablecombining an arbitrary modulation scheme and coding rate so that thetransmission rate becomes larger in order of the MCS from MCS=1 to MCS=4is used. Furthermore, a case has been explained in Embodiment 4 wherethe transmission power level of a directional transmission signal iscontrolled so that the received power level of a received signal becomesgradually larger from two frames before the frame in which directionaltransmission signal #1204 is received for the first time, but this is byno means limiting and is also applicable to cases where the power levelof a directional transmission signal is controlled so that the powerlevel of a received signal of a directional transmission signal at thereceiving side becomes gradually larger in other frames than the frametwo frames before the frame in which directional transmission signal#1204 of a predetermined power level is received for the first time.

Embodiment 5

FIG. 15 is a block diagram showing a configuration of directional signalgenerating section 111 according to Embodiment 5 of the presentinvention.

As shown in FIG. 15, directional signal generating section 111 accordingto Embodiment 5 removes gain control signal generating section 201 andgain control signal multiplex section 203, has modulation section 1403in place of modulation section 202 and transmission level controlsection 1405 in place of transmission level control section 204, andadds spreading selection section 1401, error correcting coding section1402 and spreading section 1404 in directional signal generating section111 according to Embodiment 1 shown in FIG. 3. In addition, parts inFIG. 15 that have identical configurations with ones in FIG. 3 will beassigned the same codes as in FIG. 3 without further explanations.Configurations of a transmission/reception apparatus and a receptionapparatus that is a communicating party of a transmission/receptionapparatus has the same configurations as FIG. 2 and FIG. 4, andtherefore the explanation thereof is omitted.

Spreading factor selection section 1401 selects the spreading factor ofa directional transmission signal in the case where timing controlinformation is inputted. That is, spreading factor selection section1401 selects the spreading factor so that the spreading factor becomessequentially smaller from a directional transmission signal of smalltransmission power level to a directional transmission signal ofpredetermined largest transmission power level. Spreading factorselection section 1401 outputs spreading factor information that isinformation indicating the selected spreading factor to spreadingsection 1404. Spreading factor selection section 1401 outputs a timingcontrol signal that is information of the timing when the selection ofthe spreading factor is started to transmission level control section1405.

Error correcting coding section 1402 codes a directional transmissionsignal and outputs the result to modulation section 1403.

Modulation section 1403 modulates directional transmission data inputtedfrom error correcting coding section 1402, generates a directionaltransmission signal, and outputs the generated directional transmissionsignal to spreading section 1404.

Spreading section 1404 performs spreading processing on the directionaltransmission signal inputted from modulation section 1403 using apredetermined spreading code and outputs the result to transmissionlevel control section 1405.

Transmission level control section 1405 sets the transmission powerlevel of the directional transmission signal inputted from spreadingsection 1404 from timing control information inputted from spreadingfactor selection section 1401 at a timing when a directionaltransmission signal is inputted from spreading section 1404 so that thetransmission power level becomes gradually larger up to a predeterminedlevel for each frame. Transmission level control section 1405 outputs adirectional transmission signal to adder 113 and multipliers 112-1 to112-n after the transmission power level is set.

FIG. 16 illustrates relationships between the received timing and thereceived power level of nondirectional received signal #1501 anddirectional received signal #1502, #1503 and #1504 received at areception apparatus. In addition, a view showing the change of the rangeof the dynamic range of AGC is the same as FIG. 5B, and therefore theexplanation thereof is omitted.

As shown in FIG. 16, a transmission/reception apparatus receives areceived signal in which nondirectional received signal #1501 anddirectional received signal #1502 are code multiplexed, at time t1 whenthe frame two frames before the frame including directional receivedsignal #1504 is received. The received signal in which nondirectionalreceived signal #1501 and directional received signal #1502 are codemultiplexed has a larger power level corresponding to the directionalreceived signal #1502 multiplex than the power level of nondirectionalreceived signal #1501. Furthermore, the received signal in whichnondirectional received signal #1501 and directional received signal#1502 are code multiplexed has a smaller power level than the powerlevel of a received signal in which nondirectional received signal #1501and directional received signal #1504 are code multiplexed. Therefore,the transmission/reception apparatus at the receiving side controls again according to the received power level of the received signal inwhich nondirectional received signal #1501 and directional receivedsignal #1502 are code multiplexed, and thereby increasing the dynamicrange from time t1.

Further, the transmission/reception apparatus receives a received signalin which nondirectional received signal #1501 and directional receivedsignal #1503 are code multiplexed in the next frame of the frameincluding the received signal in which nondirectional received signal#1501 and directional received signal #1502 are code multiplexed. Thereceived signal in which nondirectional received signal #1501 anddirectional received signal #1503 are code multiplexed has a largerpower level corresponding to the directional received signal #1503multiplex than the power level of nondirectional received signal #1501.The power level of directional received signal #1503 is larger than thepower level of directional received signal #1502, and therefore islarger than the power level of the received signal in whichnondirectional received signal #1501 and directional received signal#1502 are code multiplexed. The received signal in which nondirectionalreceived signal #1501 and directional received signal #1503 are codemultiplexed has a smaller power level than the power level of a receivedsignal in which nondirectional received signal #1501 and directionalreceived signal #1504 are code multiplexed. Therefore, thetransmission/reception apparatus at the receiving side controls a gainaccording to the received power level of the received signal in whichnondirectional received signal #1501 and directional received signal#1503 are code multiplexed, thereby making it possible to set a dynamicrange including the power level of the received signal in whichnondirectional received signal #1501 and directional received signal#1504 are code multiplexed at time t2.

The spreading factor is selected for directional received signals #1502,#1503, and #1504 according to the transmission power level at spreadingfactor selection section 1401. That is, spreading factor SF=16 is setfor directional received signal #1502, spreading factor SF=8 is set fordirectional received signal #1503, and spreading factor SF=4 is set fordirectional received signal #1504. Here, the spreading factor becomessmaller at SF=16, SF=8, and SF=4 in order.

In this way, according to Embodiment 5, in addition to the aboveadvantages of Embodiment 1 and Embodiment 3, the transmission powerlevel of a directional transmission signal is set so as to graduallybecome larger up to a predetermined level, and spreading factor isselected according to the transmission power level, and therefore it ispossible to prevent deterioration of error rate characteristic andreliably perform reception demodulation at the receiving side.

In addition, a case has been explained in Embodiment 5 where the powerlevel is made different for each frame, but this is by no means limitingand is also applicable to cases where the power level is made differentat an arbitrary timing such as for each slot. Furthermore, a case hasbeen explained in Embodiment 5 where directional transmission signal#1502 and #1503 subject to gain control and a nondirectionaltransmission signal are code multiplexed, but this is by no meanslimiting and is also applicable to cases where a nondirectionaltransmission signal is not transmitted when directional transmissionsignal #1502 and #1503 are transmitted. Still further, a case has beenexplained in Embodiment 5 where the transmission power level of adirectional transmission signal is controlled so that the power level ofa received signal of a directional transmission signal becomes graduallylarger from two frames before the frame in which directionaltransmission signal #1504 of a predetermined power level is received forthe first time, but this is by no means limiting and is also applicableto cases where the power level of a directional transmission signal iscontrolled so that the power level of a received signal of a directionaltransmission signal at the receiving side becomes gradually larger inother frames than the frame two frames before the frame in whichdirectional transmission signal #1504 of a predetermined power level isreceived for the first time.

Embodiment 6

FIG. 17 is a block diagram showing a configuration oftransmission/reception apparatus 1600 according to Embodiment 6 of thepresent invention.

As shown in FIG. 17, transmission/reception apparatus 1600 removesdirectional signal generating section 111, and adds control signalgenerating section 1601, control signal multiplex section 1602 andmodulation section 1603 in transmission/reception apparatus 100according to Embodiment 1 shown in FIG. 2. In addition, parts in FIG. 17that have identical configurations with ones in FIG. 2 will be assignedthe same codes as in FIG. 2 without further explanations.

Control signal generating section 1601 obtains a ratio between thereceived power of a received signal at one antenna 101-1 inputted fromdetecting section 104-1 and the received power of a received signalreceived with directivity inputted from combining section 107, andgenerates a control signal including information of the obtained ratioof the received power and information of a timing when a directionaltransmission signal is transmitted (power level information.) Controlsignal generating section 1601 outputs the generated control signal tocontrol signal multiplex section 1602 at a timing of the frame threeframes before the frame in which the transmission of directionaltransmission signals starts based on timing control information. Inaddition, a control signal is not limited to the ratio of the receivedpower, and may be information of difference between the received powerof a received signal received at one antenna 101-1 inputted fromdetecting section 104-1 and the received power of a received signalreceived with directivity at a plurality of antennas 101-1 to 101-ninputted from combining section 107.

Control signal multiplex section 1602 multiplexes the nondirectionaltransmission signal inputted from modulation section 110 including acontrol signal and outputs the result to adder 113.

Modulation section 1603 modulates a directional transmission signal,generates a directional transmission signal and outputs the generateddirectional transmission signal to multipliers 112-1 to 112-n.

Adder 113 adds the control signal and the nondirectional transmissionsignal inputted from control signal multiplex section 1602 and thedirectional transmission signal inputted from multiplier 112-1, therebytime division multiplexing a control signal and a directionaltransmission signal and outputting the result to RF section 114-1.

Next, a configuration of transmission/reception apparatus 1700 that is acommunicating party of transmission/reception apparatus 1600 will bedescribed using FIG. 18. FIG. 18 is a block diagram showing aconfiguration of transmission/reception apparatus 1700.

As shown in FIG. 18, transmission/reception apparatus 1700 according toEmbodiment 6 adds received level determining section 1701 totransmission/reception apparatus 300 according to Embodiment 1 shown inFIG. 4. In addition, parts in FIG. 18 that have identical configurationswith ones in FIG. 4 will be assigned the same codes as in FIG. 4 withoutfurther explanations.

Received level determining section 1701 extracts the control signal fromthe demodulated received signal inputted from modulation section 305 andcan learn the received power level of the directional transmissionsignal transmitted from transmission/reception apparatus 1600 from theextracted control signal, and therefore determines the received powerlevel of the directional transmission signal using the control signal.Received level determining section 1701 outputs information of thedetermined received power level of the directional transmission signaland information of the received timing to AGC control section 307.

AGC control section 307 determines a gain for variable gain amplifier304 so that the received level measured by detecting section 306 becomesa desired received level by the similar method to the above describedEmbodiment 1 and outputs gain information that is information of thedetermined gain to gain switching section 308. On the other hand, in thecase where information of the received power level and the receivedtiming is inputted from received level determining section 1701, AGCcontrol section 307 determines a gain without using the detection resultof received level detecting section 306, corresponding to the receivedpower level determined at received level determining section 1701 at thetiming when a directional transmission signal is received by theinformation of received timing inputted from receiving level determiningsection 1701, and outputs gain information that is information of thedetermined gain, to gain switching section 308.

FIG. 19 illustrates relationships between the received timing and thereceived power level of nondirectional received signal #1801, #1802 and#1804, and directional received signal #1803 received at a receptionapparatus. In addition, a view showing the change of the range of adynamic range of AGC as time passes is the same as FIG. 5B, andtherefore the explanation thereof is omitted.

As shown in FIG. 19, a reception apparatus extracts control informationincluded in nondirectional received signal #1801 at time t0 when theframe three frames before the frame including directional receivedsignal #1803 is received, and learns the transmission power ofdirectional received signal #1803. By this means, it is possible toincrease the dynamic range from time t1 and set a dynamic rangeincluding the power level of directional received signal #1803 at timet2 when directional received signal #1803 is received.

In this way, according to Embodiment 6, information of the differencebetween the power level of a nondirectional transmission signal and thepower level of a directional transmission signal is included in anondriectional transmission signal, and the information of thedifference is transmitted at timing a little before the timing of thetransmission of a directional transmission signal, and therefore it ispossible to set a large dynamic range before a directional transmissionsignal is received, thereby making it possible to lower the possibilityof failing reception demodulation and prevent deterioration oftransmission efficiency caused by retransmission.

In addition, a case has been explained in Embodiment 6 where a controlsignal is transmitted in a frame three frames before the frame in whichthe transmission of directional transmission signals starts, but this isby no means limiting and is also applicable to cases where a controlsignal is transmitted in an arbitrary frame before the frame in whichthe transmission of a directional transmission signal starts, and acontrol signal is transmitted at an arbitrary timing a predeterminedtime before a directional transmission signal is transmitted.Furthermore, a case has been explained where a control signal istransmitted in a frame three frames before the frame in which adirectional transmission signal is transmitted, but this is by no meanslimiting and is also applicable to cases where a control signal istransmitted in the same frame as the frame in which a directionaltransmission signal is transmitted.

In addition, transmission/reception apparatus 100, 500 and 1600 ofabove-described Embodiment 1 to Embodiment 6 are applicable tocommunication terminal apparatus or base station apparatus. Furthermore,transmission/reception apparatus 300, 700 and 1700 of above-describedEmbodiment 1 to Embodiment 6 are applicable to base station apparatus orcommunication terminal apparatus.

INDUSTRIAL APPLICABILITY

The transmission/reception apparatus and gain control method of thepresent invention can lower the possibility of failing receptiondemodulation in communication where data is transmitted with and withoutdirectivity and has advantages of preventing deterioration oftransmission efficiency caused by retransmission, and is useful in gaincontrol.

The present description is based on the Japanese Patent Application No.2003-385081 filed on Nov. 14, 2003, entire content of which is expresslyincorporated by reference herein.

1-17. (canceled)
 18. A transmission apparatus comprising: a gain controlsignal generating section that generates a gain control signalcomprising a signal for adjusting a gain for a received signal of acommunicating party; a gain control signal multiplex section that timedivision multiplexes a directional transmission signal and the gaincontrol signal so that the gain control signal is transmitted apredetermined time before a frame in which the directional transmissionsignal is transmitted in bursts; a transmission level control sectionthat sets a transmission power level of the gain control signal so thata transmission power level of the gain control signal is smaller than atransmission power level of the directional transmission signal and areceived power level of the gain control signal is larger than areceived power level at a communicating party of a nondirectionaltransmission signal; and a transmission section that transmits thedirectional transmission signal and the gain control signal at thetransmission power level set at said transmission level control sectionwith directivity, and transmits the nondirectional transmission signalwithout directivity.
 19. The transmission apparatus according to claim18, comprising a code multiplex section that code multiplexes thenondirectional transmission signal and the gain control signal, wherein:said transmission level control section sets the transmission powerlevel of the gain control signal so that the received power level addingthe received power level of the gain control signal code multiplexed atsaid code multiplex section and the received power level of thenondirectional transmission signal is smaller than the received powerlevel of the directional transmission signal; and said transmissionsection transmits the gain control signal and the directionaltransmission signal with directivity and transmits the nondirectionaltransmission signal without directivity.
 20. The transmission apparatusaccording to claim 18, wherein said transmission level control sectionobtains a received power level ratio between a received power level of areceived signal at one antenna receiving a signal transmitted from acommunicating party and a received power level of a received signal inwhich a signal transmitted from the communicating party is received withdirectivity at a plurality of antennas including said one antenna, andsets a transmission power level of the gain control signal so that apower level obtained by dividing a transmission power level of the gaincontrol signal by the received power level ratio is larger than atransmission power level of the nondirectional transmission signal. 21.A transmission apparatus comprising: a control signal multiplex sectionthat time division multiplexes a directional transmission signal andpower level information so that the power level information comprisinginformation of a received power level at the communicating party of thedirectional transmission signal is transmitted to the communicatingparty before the directional transmission signal is transmitted; and atransmission section that transmits the power level information and thedirectional transmission signal multiplexed at said control signalmultiplex section with directivity.
 22. The transmission apparatusaccording to claim 21, comprising a control signal generating sectionthat obtains a received power level ratio between a received power levelof a received signal at one antenna receiving a signal transmitted fromthe communicating party and a received power level of a received signalin which a signal transmitted from the communicating party is receivedwith directivity and generates the power level information comprisinginformation of the received power level ratio, wherein said controlsignal multiplex section time division multiplexes the directionaltransmission signal and the power level information so that the powerlevel information generated at said control signal generating section istransmitted to the communicating party.
 23. A reception apparatuscomprising: a received level detecting section that obtains a receivedpower level of a gain control signal comprising a signal for adjusting again for a received signal included in the received signal and areceived power level of the received signal other than the gain controlsignal; a gain setting section that sets a gain based on a receivedpower level of the gain control signal measured at said received leveldetecting section and the received power level of the received signalother than the gain control signal; and a gain adjusting section thatamplifies a gain for the received signal at the gain set at said gainsetting section.
 24. The reception apparatus according to claim 23,wherein said gain setting section sets a gain corresponding to anaverage value of measurement values of the received power level measuredat said received level detecting section, averaged over a predeterminedtime, when the gain control signal is not received, and sets a gaincorresponding to the measurement value measured at said received leveldetecting section when the gain control signal is received.
 25. Areception apparatus comprising: a gain setting section that sets a gaincorresponding to power level information comprising informationindicating a received power level after a predetermined time included ina received signal; and a gain adjusting section that amplifies thereceived signal at the gain set at said gain setting section.
 26. A gaincontrol method comprising steps of: generating a gain control signalcomprising a signal for adjusting a gain for a received signal of acommunicating party; time division multiplexing a directional signal andthe gain control signal so that the gain control signal is transmitted apredetermined time before a frame in which the directional signal istransmitted in bursts; setting a transmission power level of the gaincontrol signal so that a transmission power level of the gain controlsignal is smaller than the transmission power level of the directionalsignal and a received power level of the gain control signal is largerthan a received power level of a nondirectional signal at acommunicating party; transmitting the directional signal and the gaincontrol signal at the set transmission power level with directivity andtransmits the nondirectional signal without directivity; and controllinga gain at a dynamic range including the received power level of thereceived nondirectional signal, the gain control signal and thedirectional signal.